The present invention relates generally to a method and apparatus that allows an area of biologic tissue such as the skin to be affected by alteration of its normal temperature,,and by a variety of different kinds of radiation. The method and apparatus allow these effects of temperature change and irradiation to occur simultaneously.
Radiation from various portions of the spectrum is currently utilized in the treatment of a variety of skin conditions. Lasers, intense pulsed light. sources and other radiation emitting devices have been used to treat conditions including birthmarks, tattoos, benign vascular lesions, pigmented lesions, scars, warts, stria distensae, wrinkles and other benign or malignant skin lesions. Lasers and other light sources are also currently used for the removal of unwanted hair on various parts of the body.
For some of these conditions, cooling of the skin is used adjuctively to the delivery of light. Cooling is accomplished in a variety of ways. Cooling is used to reduce side effects and discomfort associated with the delivery of light in the above mentioned clinical situations. Some cooling of the skin is accomplished by the use of cold packs, or ice before and/or after light is delivered to the treatment site. Simultaneous cooling and lasing is currently accomplished by several methods.
One method of simultaneous cooling and lasing (Cool Laser Optics, Coherent Versapulse, Palomar Epitouch, Light Shear, Chill-Tip) utilizes an apparatus that subjects the treatment site to cooling delivered by a lens that is substantially transparent to the wavelength of light to be delivered to the skin. The lens must be in contact with the treatment site. This same lens is made cold by having a recirculating coolant contact an aspect of the lens other than the lens surface contacting the treatment site. A similar apparatus is used where the coolant does not recirculate, but rather is kept cool by ice that is held within the apparatus. Another apparatus sprays coolant at the lens. An index matching gel is sometimes used between the cooling lens and the surface being treated.
A problem with contact lens apparatus is an inability to make good skin contact on concave aspects of the skin surface. Although some contact cooling units have a flexible contact surface, certain areas of the skin, such as naso-ocular angle still cannot be contacted adequately. Another problem is that the lens is substantially transparent to the light being delivered. The lenses are commonly made of quartz glass or sapphire to maximize thermal conductance.
The pulsed spray cooling of the Dynamic Cooling Device (DCD) needs no contact with the treatment surface, but has other problems. DCD uses volatile liquid to spray at the skin. These substances may, or may not, have some hazard potential for the environment or for individuals inhaling these vapors. Whether these concerns are valid will require long term evaluation, and due to these concerns DCD will not be considered suitable or appropriate for some practitioners and patients.
In some instances, pre-cooled transparent gels are applied for similar purposes as stated above but without any method for maintaining a cool temperature of the gel after application to the skin.
Another kind of cooling utilizes a sprayed cryogenic liquid (dynamic cooling). The cryogenic liquid is sprayed at the treatment site just before the laser light is delivered to the skin. Evaporation of the sprayed cryogenic liquid cools the skin""s surface.
Cryogenic liquids used with DCD may cause technical problems due to frosting or icing in the delivery system. Furthermore, very exact timing is necessary with DCD to achieve the desired cooling without interfering with the transmittance of light through vaporizing sprayed cryogenic liquid or frosting of the skin. This exact timing as well as the exact quantity of. cryogenic liquid sprayed is microprocessor controlled, and any alteration due to suboptimal functioning could reduce or eliminate the benefit of treatment or cause unanticipated injury.
These various methods of cooling are utilized in an expanding list of laser amenable conditions. Specifically, contact cooling units with a cooling lens component were originally designed for use with laser treatment for lower extremity telangiectasia. These cooling units are now also used with laser treatment for other benign vascular lesions, such as port wine birthmarks, and also for laser removal of hair. Similarly, the spray cooling units are utilized for treating vascular lesions and for hair. removal. Additionally, contact and spray cooling are used for laser treatment of facial wrinkles.
All of the above apparatus and techniques are used to cool tissues. None allow the treatment site to be warmed.
There are lasers (Erbium YAG) that cause debris to be scattered during treatment. Some of these lasers have air flow directed through and out of the end of the laser hand piece. The purpose of this air flow is to prevent debris from entering the laser hand piece and clouding the laser optics inside the hand piece. The temperature of this air flow is not controlled nor is its purpose to modulate the temperature of the treatment site.
Against the forgoing background it is a primary object of the present invention to enhance the ability to alter the temperature of the skin during laser or other irradiation of the skin. Existing technology only has the ability to reduce the skin""s temperature.
It is another object of the present invention to allow heating of the skin during laser irradiation or alternatively to allow cooling.
It is still another object of the present invention to provide heating and/or cooling of the skin without making contact with the skin.
It is yet another object of the present invention to vary the temperature of the skin up or down depending on what kind of radiation is being utilized, and what condition is being treated.
Simply from the standpoint of simultaneous cooling and lasing the present invention has the additional object of avoiding problems that exist with the current cooling modalities that were mentioned above.
A further object of the present invention is to deliver warm or cool air to the skin surface without any potential for environmental or personal hazard.
It is an additional object of the present invention to avoid the use of complex technology in the delivery of a cooling medium to the treatment site so as to minimize cost to the user and maximize reliability, efficiency, and safety.